(SAR) a specific microwave radar sensor in which an effective antenna is emulated by storing and comparing the Doppler shift signals received while the aircraft travels along its flight path —note 1. this synthetic antenna (or array) is many times longer than a physical antenna, thus sharpening the effective beam width and improving azimuth resolution —note 2. good-quality SAR imagery can be obtained regardless of time of day or weather, thus offering an alternative electro-optical imagery for remote sensing of cloudy regions This definition last updated 10/23/2008